[gst-devel] Hi all, and a question

David Schleef ds at schleef.org
Tue Jun 22 11:17:24 CEST 2004

On Tue, Jun 22, 2004 at 03:49:46PM +0200, Giuliano Pochini wrote:
> On 22-Jun-2004 Benjamin Otte wrote:
> > On Sun, 20 Jun 2004, Giuliano Pochini wrote:
> >> Another little thing: cpu usage seems pretty high: ~1.2% playing mp3's and
> >> flac's, and with mp3's it's even worse. Is it normal ?  With xmms cpu usage
> >> is under 0.1%.
> >
> > GStreamer uses mad for decoding mp3s, xmms uses a different mp3 decoder (
> > I think mpg123 or similar). This might be the reason. You could try
> > madplay to know exactly.
> Yes, but libflac is the same and wav's don't need decoding at all.

Looking at the percentage cpu usage in top is completely useless
for any process that has a timing component.  Really.  Completely

I recently wrote a stress test for a driver I'm working on, which
appeared in top on sucessive refreshes as ~90%, ~80%, ~70%... down
to 10% when it jumped back to some random percentage and would
step down again.  The program was not doing anything weird and was
essentially using 0% cpu.  There was other stuff running on the
system that obvious was causing weird things to happen.  After
tracing with LTT and measuring _actual_ cpu usages, I realized that
top was just being stupid.  I've seen stuff like this a lot before,
but never with such a gross failure.


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